Computer display systems have advanced a tremendous amount since the days of the simple cathode-ray tube monitor. New flat panel monitors have a myriad of capabilities and can support a wide range of resolutions and refresh rates. They are being driven by signals compliant with new standards, such as DisplayPort, and other new standards that are currently or will be developed are sure to follow.
These computer display system may include a host or source device and a display or sink device. Other systems may use a branch device functioning as a repeater when a display is located remotely from the host. Other systems may include a branch device operating as an adapter such that a host providing DisplayPort signals can drive a legacy monitor. Still other systems may include a branch device to allow a host to provide graphics information to more than one display.
In each of these systems, it can be advantageous for a host to be able to access information regarding the display and any intervening branch device. Currently, extended display identification data (EDID) circuits are used to provide information regarding a display to a host device.
However, these extended display identification data circuits are limited in the information they can provide. Specifically, they are limited to providing supported refresh rate and resolutions, among other information. Moreover, the extended display identification data circuits are limited to information pertaining to the display device to be read by a host device; information regarding other devices is not available to the host, and this information is not available to other devices besides the host.
Thus, what is needed are circuits, methods, and apparatus for making other types of information regarding devices in a display system available to a host device, as well as making other types of information regarding devices in a display system available to other devices in the display system.